Close assist pump pics and fixing my trunk closer.

[Brett San Diego]

I'm test driving this tinypic.com site. We'll see if it works.

OK, last time I posted on this, my trunk closer did not work and I found it had been disconnected and all air line inputs plugged by the previous owner or his mechanic. This allows the trunk to be permanently set for manual closing. As I looked at the latch mechanism, it became clear that the auto trunk closing mechanism required inputs from not only the close assist pump but also the central locking pump under the rear seat. The close assist pump does the actual closing of the trunk by retracting the striker tongue in the mechanism in the trunk lid, but the central locking pump is hooked up to the trunk lid mechanism to release the striker tongue every time the trunk lid is opened so that it is ready for closing again by the close assist pump.

Here is the location of the pump in the trunk. It is simply crammed into a cube of foam above the left side wheel well.


Just pull the pump out. The lines are labelled in German. VR = vor rechts = front right door. HR = hinter rechts = rear right door. VL = vor links = front left door. HL = hinter links = rear left door. ?? = can't remember right now = trunk. SK = ?? = pump outlet line, hooked up to nothing.


I don't know if it comes this way from the factory or not, but the line to my trunk latch had been cut. A soft white rubber tubing joiner had been placed on the pump side of the line, and a screw had been inserted in the joiner to plug the line. When I removed the screw and rejoined the lines, it had a bad leak under pressure from the pump, hence the trunk closer would work twice timing out each time, then shut down. A couple plastic hose clamps solved the problem.


This black line comes from the central locking pump. It has a T-connector that should be plugged into the tongue releaser. Mine had been disconnected and plugged (again with a white rubber tubing joiner and screw) to prevent the tongue from automatically releasing. I simply plugged it back in. The other connection on the T continues to the trunk handle, also run by the central locking pump.



Brett

[Peter Guenther]

I see you got a pretty good education, I cant believe someone messed it up. My 92 had its first problems with the trunk not pulling down in 97 (out of warranty), My dealer suggested the fuse game, which worked for a while, then the doors played their game. I took the plunge and had the pump replaced, the mechanic at MB and I were on a friendly basis, suggested we do a mod that they had on a service bulletin at the same time N/C. It seems the closing assist pump develops pressure to close the doors and trunk, and then reverses to purge the system untill the next time. The handle is (was) driven of the "locking pump"!
The bulletin says to replace the latch for the later version, and drive the handle off the "closing assist pump" also by inserting a "T" and also "shorting" the microswitch connector wire. You close the lid and the handle goes in immediately, previously it happend as the lid latched.
It worked fine untill 03, I whined and they replaced the pump again, but not before checking for leaks (none) something rare at MB was a N/C. I probably have paid for it during all the other services like A/C, suspension work, but it felt good!

[Brett San Diego]

pulling and reconnecting the electrical connector on the pump. Pulling fuse 9 in the trunk has never done anything for me.

Brett